Supporting Technical Assessments

| Potential Effects of Project on Environment | WNP Wharekirauponga Underground Mine - Assessment of Effects of Discharges to Air | 4397169-66885702-23 | | 39 7 Potential Effects of Project on Environment 7.1 Potential Adverse Effects of Discharges to Air The potential adverse effects from the discharge of dust (particulate matter) include: ● Nuisance effects generally associated with deposited dust and the coarser fraction of TSP such as soiling, effects on amenity and visibility ● Health effects from exposure to inhalable dust (PM10, PM2.5 and respirable crystalline silica as these finer particles can penetrate the nose and mouth if inhaled and can enter the lungs and respiratory tract) ● Effects on flora and fauna. 7.2 Approach to Assessment of Effects 7.2.1 Overview For consent applications with a number of potential intermittent diffuse sources of dust (e.g WRS and topsoil storage), as well as dust from point sources (e.g vents and portals) over a hilly site, it is difficult and impractical to estimate likely overall site emission rates using dispersion modelling techniques. Where these constraints are present, qualitative methods should be used. The historical and existing effects of the Waihi Mine activities (surface and underground) have also been used to assess the potential impacts of the Willows Road project on nearby sensitive receptors (dwellings). This includes analysing the results of the past 20 years of monitoring data, as well as assessing complaints received over this period. The significantly larger Waihi site lies within a more sensitive receiving environment than the Willows Road site and includes an open pit operation (not proposed at Willows Road). The Waihi site therefore provides an effective “worst case” scenario against which the likely air discharge effects of tunnel construction and underground mining can be assessed. The likelihood of each of the potential sources of dust at the site resulting in adverse effects on the nearest sensitive receptors has been assessed, taking into account the location of the receptor relative to the source, the likely frequency of potential impacts and the likely severity (intensity and duration) of the potential impact. Where an elevated risk of adverse effects occurring has been identified, additional dust control and monitoring methods are recommended to mitigate the risk. The risk factors assigned to each sensitive receptor group are in accordance with the factors shown in Table 7-123. 23 The risk factors shown in Table 7-1 are based on the risk assessment procedure recommended in Guidance on the Assessment of Mineral Dust Impacts for Planning” published by the Institute of Air Quality Management in May 2016.

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